This invention relates generally to rectifier bridges assemblies utilized with, for example, an automotive alternator. More specifically, the present invention relates to a rectifier bridges assembly having redesigned heat sinks and which eliminate the use of a connection plug between the rectifier bridges assembly and the current output leads to a battery.
A rectifier bridges assembly, commonly called a rectifier, is one of the components parts of an alternator assembly forming a portion of the electrical charging system in an automobile. The basic role of the charging system is to replenish the charge of a battery with electricity generated by the alternator. The electrical current generated by the alternator is an alternating current (AC), while the electrical current preserved in the battery is a direct current (DC). The alternating current must be converted to a direct current so that the battery can be charged. This conversion is called rectification, and is the specific function of a rectifier bridges assembly.
The alternator used in a typical automobile is a three-phase type of alternating current (AC) electrical generator. The electricity generated by each phase must be rectified by one rectifier bridge. Each rectifier bridge consists of two diodes and, thus, three rectifier bridges are required for one alternator. Therefore, a typical rectifier bridges assembly consists of three rectifier bridges with six diodes. Three of the six diodes are connected to a ground, and the other three diodes are connected for DC output charging to the battery.
During the rectification process, tremendous amounts of heat are generated by converting the alternating current (AC) to direct current (DC). The heat must be dissipated as quickly and efficiently as possible, or the diodes may be ruined within a relatively short period of time. Therefore, the rectifier bridges are normally soldered onto heat sinks of good heat-conductive materials. Usually a portion of the ground provides a negative heat sink, and some structure associated with the DC output charging to battery provides a positive heat sink that is conductively and terminally isolated from the ground.
Rectifier bridges assemblies are normally assembled as an integrated part of an alternator assembly. The electrical current output of the alternator to the battery greatly depends on the capacity of the rectifier bridges assembly to rectify the alternating current to a direct current. However, the rectification ability of the rectifier bridges assembly with the diodes at a set power level depends heavily on the heat disbursing ability of the heat sinks utilized. The faster heat can be disbursed from the rectifier bridges assembly, the cooler the rectifier can operate. The rectifier also has a longer life and a greater rectification capacity. Hence, the capacity of the heat sink(s) should be a major concern in the design of a rectifier bridges assembly.
Most rectifier bridges assemblies used in automobiles have two heat sinks, one for the negative side and the other for the positive. This, however, is not always the case. For example, in the rectifier bridges assembly used on Ford Motor Company's 2 G alternators, all six diodes are soldered onto only one heat sink within an area not greater than 3.6 square inches. This particular design, which is common in the industry, tends to have a very poor heat disbursing capacity. Besides the small heat sink area, the current output leads are connected with a socket and plug and are both constructed of a plastic housing. Electrical arcing occurs between the terminals of the socket and plug due to constant vibration while the alternator is working. The poor heat disbursing capacity of such rectifiers makes them fail much easier and prematurely, and the electrical arching inherent in the socket and plug design burns or corrodes the connection terminals.
Accordingly, there has been a need for a novel rectifier bridges assembly that overcomes the above-noted problems in prior art designs by utilizing two separate heat sinks and by eliminating the use of socket and plug connections to make the design electrically arching-free. Such a novel rectifier bridges assembly must be adapted for use with standard alternator assemblies and have a design that may be manufactured cost effectively. The present invention fulfills these needs and provides other related advantages.